There are many forms of packages for containing and dispensing flowable materials and the particular form has usually been chosen in regard to the predominant characteristic of the flowable material to be dispensed. For example, liquids of relatively low viscosity are usually packaged in screw or friction-type capped bottles. Moderately viscous liquids, such as hand lotions, are often packaged in a hand pump bottle or a flexible squeeze bottle in order to aid in dispensing the liquid from the package. When the geometrical shape of the dispensed stream is important, special shape forming dispensing means are provided, e.g. when a spray is desired an atomizing hand pump is often provided in the package.
Packages of the foregoing nature, and known modifications thereof, are not effective for dispensing flowable materials of high viscosity. For example, viscous hand lotion, face cream, toothpaste and like viscous suspensions and gels require greater pressure for satisfactory dispensing than can be conveniently achieved by conventional hand pumps and gravity.
Packages pressurized with chlorofluorohydrocarbons have been used for dispensing these more viscous flowable materials, but such pressurized packages do present problems, such as greater expense, possible explosion, leakage of the propellant and, as recently demonstrated, released propellant which can be dangerous to the environment. Thus, the art has sought ways to avoid the use of pressurized packages for dispensing viscous flowable materials. U.S. Pat. No. 3,208,645, issued to Rayner in 1965, discloses a package for dispensing flowable materials of a cream-like consistency wherein a lower open topped container has disposed therein an upper cylindrical plunger, the bottom of which engages essentially the entire cross-section of the container and thus is capable of exerting considerable pressure on the cream-like consistency contents in the lower container. The plunger is also open-topped but is provided with a cover (closure). Wing elements and friction portions on the side and underside of the cover frictionally engage the upper end of a dispensing channel, the lower end of which communicates with an orifice in the bottom of the plunger. Thus, a pathway for the flowable material is provided from the lower container through the channel and out of a dispensing orifice formed between the upper end of the channel and the wing elements and friction portions.
While the foregoing package arrangement provides advantages in the art, it does suffer from several decided disadvantages. First of all, the hollow plunger must have an overall volume essentially as great as the volume of the lower container. Thus, the shipping volume of the package is essentially twice the volume necessary to contain the flowable material. Also, since the wing elements and friction portions of the cover must closely mate with the upper end of the dispensing channel in order to make a completed passageway, accurate molding of the package and careful positioning of the cover on the plunger must be accomplished in order to insure a relatively fluid-tight passageway. As can be appreciated, any substantial deviation from that accuracy will allow the mating of the wing elements and frictional portions with the upper end of the channel to be less than fluid-tight and in operation of the package flowable material may pass between these mating surfaces and be lost into the interior of the plunger.
It would be, therefore, of considerable advantage in the art if the ratio of the volume of packaged flowable material to package volume could be increased beyond the essentially 0.5:1 of the above-discussed prior art package. It would be of even further advantage in the art if the problems associated with providing a passageway, as noted above, could be avoided, particularly in regard to the possibility of the packaged flowable material passing between the mating surfaces of the cover and channel and being lost into the interior of the plunger. It would be of even further advantage to the art to provide a package which is convenient for use in dispensing materials of the nature discussed above, but in addition thereto dispense yet a further flowable material. This would allow a dual package for materials commonly concurrently used, such as baby oil/baby powder, mustard/catsup, sugar/cream, suntan oil/suntan cream, and the like. Finally, it would be a decided advantage to the art to produce packages of the foregoing nature which do not require accurate assembly of parts for functional operation, and where all functional parts, particularly the passageway for the viscous flowable material, are integrally molded, e.g. from a plastic material or the like.